Yes, you should. Unless you have a contagious illness or some kind of injury, you should follow through with your appointment for a couple of reasons.
- That’s what performers (people) of integrity do. If they are able to sing, they sing when they have agreed to sing.
- Learning how to perform when you aren’t feeling “100%” is essential to reducing anxiety and increasing success. We’re human. Things aren’t always perfect and we have to learn how to deal with that. Your teacher can help you with how to warm up and which adjustments to make under these circumstances. It’s valuable knowledge.